Re: What Gauge Wire?
Wire is rated to amp loads. Every electrical device draws X number of amps. There will be resistance in the wire, the longer the run the higher the resistance. MAtch the run length and amp draw to get the correct wire gauge.
In general, 16 gauge will work for most circuits, lights, bilge pump, nav lights, fish finder, etc. When I rebuilt my boat I used trailer wiring. It's 4 color coded wires attached to one another, generally 25' long, about $12, and 16 gauge. It may not be tinned, but if you seal teh connections with Di-electric grease you wont have any problems. Think of it this way, there are billions of cars/trucks in the Us and none of them use tinned wire. Ever have trouble in the rain?